Transcriptome analysis of Pyrus pyrifolia watercore by comparing susceptible and non-susceptible F1 sib pairs

Watercore is a physiological disorder develops in the Japanese pear fruit showing a watery translucent area in the flesh while on the tree and lead to the loss of commercial value. The sustainability to watercore is one of the most important characterization to be studied it the breeding of the Japanese pear. However, even in susceptible cultivars like ‘Hosui’, the degree of watercore development is significantly different from year to year, this makes it difficult to analyze the characteristic phenomena prior to watercore development. We’d obtained two reproducible sib strains, that is, susceptible strains developed severe watercore in all of the fruit every year while no watercore was found in the non-sustainable ones even when they were overmatured. They are originated from ‘Hosui’ x ‘Hogetsu’ and ‘Akiakari’ x ‘Taihaku’. In order to search the genes related to watercore, we used these susceptible and non-susceptible F1 sib strain pairs. By using pear custom microarray, the genes that differed in expression level prior to watercore development were extracted. The sugar-metabolism, hormone, and cell wall related genes were identified in the 105 differentially expressed genes. Some of them showed different expression levels only in the immature stages prior to watercore development. The gene expression profiles between watercore susceptible pears and sustainable pears